In recent years, a home system, for example, a home energy management system (HEMS), is widespread in which a power generation facility as represented by photovoltaic generation is introduced. This home system can appropriately manage power of a home in general.
Power storage facilities such as electric vehicles and stand-alone type batteries are often introduced in the home systems. As background technology of the home system in which a power generation facility and a power storage facility are introduced, for example, Patent Literature 1 discloses an invention of a power storage type power generation system that can store power from a power generation facility or a commercial power system (commercial power source). In addition, Patent Literature 2 discloses an invention of a load control device that uses surplus power of an electrical generator to operate a load device.